Mesoporous SiO2 nanopowder was synthesized under an acidic condition by a sol-gel method using various amounts of cetyltrimethyl ammonium bromide (CTAB) as structure directing agent. The samples were investigated with XRD, SEM, FTIR, TEM and N2 absorption-desorption analysis. Also, the incremental effect of surfactant were examined. The results obtained from the analysis suggested that an increase in the amount of surfactant resulted in increasing specific surface area, pore size and pore volume, of the synthesized particles up to 549 m2.g-1, 17.3 nm, and 2 cm3.g-1, respectively. Absorption behavior of the mesoporous silica was investigated for degradation of methylene blue pigments (MB) in aqueous solutions. The samples SC0, SC0.5 and SC1 showed the maximum absorption capacities of 333, 454 and 526 mg/g, respectively